use a 20 deg dome piston.
you can end up with 100-110 cc heads it doesn't matter.
cut the 20 deg radius into the head.
fit and check cc cylinder and head .
you will be somewhere between 14.0 17.5
if your porter can cut the 20 deg radius in the head ,then let him cut it.
Randy is getting the pistons/cylinders for you and doing your crank work already from what you posted earlier?
send the motor to him.
if your porter cant cut the 20 deg radius in the head then let randy cut them . he will be cutting your valve reliefs and cutting the piston to bring it into the desired compression anyway.
he is more than capable.

That's kind of funny actually and no discredit Jim
I would like Randy to respond on this forum.
I would like him to tell the public what he told me on the phone when I called him with a similar situation.
Short answer was not no maybe or yes,
It was Hell no and he had strong reasons to back it up, not sales.
I would do it in a heartbeat if the dome could safely reduced so that total piston weight was in the 500g gross neighborhood, had safe street cross sectional areas, and it was full skirted. Another challenge.

That's kind of funny actually and no discredit Jim
I would like Randy to respond on this forum.
I would like him to tell the public what he told me on the phone when I called him with a similar situation.
Short answer was not no maybe or yes,
It was Hell no and he had strong reasons to back it up, not sales.
I would do it in a heartbeat if the dome could safely reduced so that total piston weight was in the 500g gross neighborhood, had safe street cross sectional areas, and it was full skirted. Another challenge.

well if he dosent/wont do it, I know someone that can.
two 117 ci motors owned by forum members right here making 150-170 hp one with baisley hurricane heads and one with WFO Larry 110 heads,both running this piston.
all you can do is give the advice. I really dont care to hear someone explain why something that has been done several times already ,cant be done.
11.3:1 with the 640,and whatever piston they want to use will be fine anyway. go for it.

That's why I left it up to Randy@Hyperformance. I have built a handful of mouse motors/top end builds, but this a ground up, big power, build better left to a pro. I am completely confident with Randy and his piston choice. I'm betting at least 140hp...safe bet.

My comments are in agreement with all I believe. This is a complex build and integration will make or break. Mother my hopes are you end up with a motor that is done, no screwing around after the fact. Best case is the pro helping is the same guy calling the shots on pistons and headwork. Just a little cleaner that way. In this case I know Randy and trust him very much. My opinion is just one in the sea of them but really 140? A crate motor with a head mill can do that. I would hope that when using higher end hardware, which is where you are at with Hurricane heads you would be looking for more.
Just my 2c
I am not vying for this work either.

The reason I don't like that style of setup with the angle squish cut is exactly the same reason I don't like the old httc setups, it boils down to too much weight above the piston pin and can result in premature skirt damage, I am not saying it wont work but the longevity would certainly be better with a flat top and a cut chamber.
As for that valve protrusion thing to try to put it in less technical terms than Don, as the valves are sunk further into the head they move farther apart from each other(because of the angle) to begin with which adds to clearance when they are both at lift compared to if they were closer to start with.

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